Commutator-cylinder for dynamo-electric machines.



W. S. PYRAH.

COMMUTATOR CYLINDER FOR DYNAMO ELECTRIC MACHINES.

APPLICATION FILED MAR.24| 1915.

Patented May 1, 1917.

INVENTOR W////'c2m Sidney Pyrdh.

[ATTORNEY UNITED STATES PATENT OFFICE.

WILLIAM S. PYBAH, OF OLD TRAFFORD, ENGLAND, ASSIG-NOR TO WESTINGHOUSE ELEC- TRIC-ANP MANUFACTURING COMPANY, A

CORPORATION OF PENNSYLVANIA.

I COMMUTATOR-CYLINDER FOR DYNAMIC-ELECTRIC MACHINES.

, To all whom it may concern:

Be it known that 1, WILLIAM S. PYRAH,

- Cylinders for Dynamo-Electric lVIachines,

of which the following is a specification.

My invention relates to commutator cylinders for dynamo-electric machines, and it has for its object to improve the construction of such devices in order that the development of displaced conducting segments commonly known as high bars, and similar irregularities on the surface of the cylinder may be prevented. a

"In the manufacture of commutator cylinder's, the alternate conducting and insulating segments are assembled together to form a ring or cylinder and are held in position by metal rings of V-shape in crosssection located at each end which engage correspondingly shaped notches in the ends of the assembled commutator segments. The rings, commonly called V-rings, are drawn together by the use of through bolts or other suitable means so as to firmly grip the segments of the commutator. In order to prevent the occurrence of short-circuits, insulating means" must be interposed between the ends of the segments and the metal V-rings, and the best material for this purpose is built-11p n1ica which is formed of scales of mica held together by a suitable binder, such as shellac varnish. It is obvious, from"the nature of the material, that built-up mica is not a perfectly homogeneous substance but that parts of it are softer that others. In assembling the parts of a commutator cylinder, the assembled segments are placed in position, with a suitable thickness of built-up mica interposed between their ends and the V-rings, and the latter are drawn toward each other through bolts or other suitable means so that the built-up mica is strongly compressed. The periphery of the commutator cylinder is then turned true and, if necessary, may again be trued up before the completed machine is put into actual service. After the machine has been in service, it may be found that the surface of the commutator cylinder has become irregular and that some segments project beyond others, formzing Specification of Letters Patent.

What are commonly known as high-bars.

These irregularities give rise to various difficulties the effects of which are shown in chattering of the brushes and in sparking. The alteration in the form of the commutator cylinder is due to the expansion and 0 contraction of the segments that are caused by variations in temperature and by a lack of homogeneity in the layer of insulation between the ends of the bars and the V-rings on account of which the thickness of the insulation becomes non-uniform. In other words, the contact between the ends of the commutator segments and the built-up mica insulation is largely point-and-line contact instead of surface contact and consequently,

some of the segments become loose and are displaced by centrifugal force.

According to the present invention, ir-

regularity and want of homogeneity in the built-up mica insulation is compensated for by inserting between such insulation and the surfaces of the V-rings to which it is applied layers of lead or other suitable material which, although rigid and practically incompressible, has the property of flow 0 ing readily under pressure. Durin the assembly of the commutator cylin er, the pressure applied to draw the V-rings toward each other causes the lead or other material to flow in such a manner as to compensate for the irregularities in the built-up mica insulation. The spaces between the V-rings and commutator segments become completely filled with the material and the compression is substantially uniform at all parts. The

result of this is that approximately complete. surface contact occurs and is maintained between the ends of the segments andthe insulation. It is found that, with this construction, when once the corrimutator has been trued up, it remains so under all ordinary conditions of service.

The single figure of the accompanying drawing is a longitudinal sectional view of a portion of a structed in accordance with my invention.

The sleeve or bushing 1 on which the commutator cylinder is built up is secured to the shaft of the machine in any suitable manner, vided'w-ith V-shaped notches 3 in the ends thereof, are, held in position by the V-rings 4 which engage the notches 3 and are drawn Patented May 1, 1917.

Application filed March 24, 1915. Serial No. 16,801.

commutator cylinder conand a plurality of segments 2, prosaid segments, and further means interat the ends of the segments, by reason ofthe pressure, it is preferably located in recesses 8 that extend over nearly the whole of the surface of each V-ring which is in contact-with the ends of the commutator segments.

The lead or other material may be applied to the surface of the V-ring in any suitable manner. It may be spun or beaten -to form, or a number of sheets of lead of suitable size ma be placed side by side around the V-rmgs before the built-up mica insulation is applied thereto, or it may be cast into the recesses 8 provided in the V-rings 4-by means of a suitable mold.

In the place of lead, other metals or alloys having somewhat similar properties may be utllized in the presentv invention,

and the improved construction is also applicable to commutator cylinders in which insulation of a non-homogeneous kind, other than'mica, is used.

While I have shown my invention in a simple and preferred form, it is not so limited but is susceptible of various modifications of structure and arrangement of parts within the scope of the appended claims.

I claim as my invention:

1. A commutator cylinder for dynamoelectric machines comprising a plurality of assembled conducting and insulating segments, retaining means that are adapted to engage said segments, insulating means interposed between said retaining means and posed between said retaining and insulating means for preventing displacement of said conducting segments.

2. A commutator cylinder for dynamo electric machines comprising a plurality of assembled conducting and insulating segments, a plurality of V-rings that are adapted to retain said segments in position,

may

insulating means interposed between said -rings and said segments, and further means interposed between said V-rings and said insulating means for preventing displacement of said conducting segments.

3. A commutator cylinder for dynamoa electric machines comprising a plurality of 4 assembled conducting and insulating segments, a plurality of V-rings that are adapted to retain said se I ents in position, a

- plurality of layers of built-up insulation between said V-rings and said segments, and

. j acent to said segments, of soft metal disposed means interposed between said V-rings and said built-up insulation for preventing displacement of said conducting segments.

4. A commutator cylinder for dynamoelectric machines comprising a plurality of assembled conducting and insulating segments, a plurality of metal V-rings that are adapted to retain said so ents in position, a plurality of layers of uilt-up insulation interposed between said segments, and a plurality of layers of malleable material interposed between said V- rings and said built-up insulation for preventing displacement of said '?c,onducting segments.

5. A commutator cylinder for dynamoelectric machines comprising a plurality of assembled conducting and insulating segments, a plurality of metal V-rings that are adapted to retain said segments in position, a plurality of layers of built-up insulation interposed between said V-rings and said segments and a plurality of layers of soft metal interposed between said V-rings and said built-up insulation for preventing displacement of said conducting segments.

6. A commutator cylinder for dynamoelectric machines comprising a plurality of assembled conducting and insulating segments, a plurality of metal V-rings that are adapted to retain said segments ,in position,

a plurality of layers of built-up, insulation between said V-rmgs and said segments and a plurality of layers of lead interposed between said V-rings and said built-up insulation for preventing displacement of said conducting segments.

7. A commutator cylinder for dynamoelectric machines comprising a plurality of assembled conducting and insulating segments, a, plurality of metal V-r'ings that are adapted to retain said segments 1n position and are provided with recessed portions ada plurality of layers in said recessed portions, and a plurality of layers of built-up insulation interposed between said V-rings and said segments.

V 8. A commutator cylinder for dynamoelectric machines comprising a plurality of assembled conducting and insulating seg ments, a plurality of metal V'-rin that are adapted to retain said segments 1n position and are provided with recessed portions adjacent to 'said segments, a plurality of layers of lead disposed in said recessed portions, and a plurality of layers of built-u mica interposed between said V-rings an said segments.

9. A commutator cylinder. for dynamoelectric machines comprising a plurality of assembled conducting and insulating segments, a plurality of metal V-rin that are adapted to retain said segments 1n ition and are provided with portions ad V-rings and saidjacent to said segments, a plurality of laysubscribed my name this 25th day of Feb- .ers of lead molded in said recessed portions ruary, 1915. v I and a plurality of layers of built-up insula- WILLIAM S. PYRAH. tion interposed between said V-rmgs and Witnesses: 6 said segments J. S. Pnox,

In testimony whereof, I have hereunto I. W. SAUMANN." 

